I think a lot of that stuff is people buying items in bulk off alibaba, rebranding it, and listing. Most of it is crap, but that's how stuff like it can be so cheaply produced, it's one or two factories producing at scale.
All the DCRYTJT HDMI cables for a start. Got a couple of bad reviews? Just run your hand over the keyboard at random, there's your new brand name. They're now XDCRHJT HDMI cables.
On the last update, I browsed Amazon for some product, and Amazon had a pop up, kind of, that asked if I would like them to weed out fake reviews. Of course I opted in. Had it save me a couple times now.
No they literally go to the manufacturer and undercut the other businesses that use them so they can sell the item for cheaper until that business goes under, and then they raise the price. It's not just a normal stealing of a product.